The battle lines were drawn before kickoff, some more than two months ago.

The Patriots knew Buffalo would wield its league-leading run game like a hammer. So they armored up with seven combined linemen and linebackers on most early downs, just as they did at Buffalo in Week 5. In coverage, the Pats played a 50/50 split of man and zone which, compared to most games, represented a heavy man-to-man lean. That is, except for Week 5 at Buffalo when they limited the Bills’ receivers with a similar plan.

All that was left on their defensive checklist was corralling Josh Allen with a depleted front, something they barely managed with a healthy group in October. On Sunday, the Bills won because that front lost the line of scrimmage. Buffalo protected Allen throughout the day and converted 83% of the time when running on third down.

Allen also out-dueled Drake Maye in a battle between teams powered mostly by their quarterbacks. The Pats also bulked up offensively around Maye by deploying multiple tight ends and/or running backs on close to half their snaps. The plan worked. They cracked Buffalo’s bottom-5 run defense for a season-high 246 yards, plus four rushing touchdowns.

All that left offensively was Maye doing enough to keep the Bills at an arm’s length with a steady, efficient passing game. Here, he struggled.

Maye was inaccurate by his standards and at times slow to read coverage. His receivers failed him by not escaping man coverage in a few high-leverage moments, including the Patriots’ final offensive play. Buffalo bullied them at the line of scrimmage and prevented Maye from scrambling to force a turnover on downs.

Of course, special teams — and specifically kickoff coverage — were a giant mess for the Patriots. Huge. Perhaps their most troubling area after their pass rush.

Down the road, beating playoff-caliber teams like Buffalo will require reclaiming the margins they lost Sunday; like field position and yards lost on missed tackles and penalties. There’s nothing Mike Vrabel can do now about the mediocre depth on his defensive front, which was chiefly responsible for accelerating the Patriots’ slide Sunday. The Bills beat them straight up.

There is, however, more to tap into offensively, assuming Maye can rebound from the worst performance of his career by passer rating. It might be unreasonable to ask a 23-year-old to out-gun the league’s reigning MVP in a shoot-out. But if the Patriots meet the Bills again, another shoot-out will ensue because the battle lines in this matchup are established.

“It’s no secret, you know what I mean?” Vrabel said of the second half. “(We) called the same stuff, they called the same stuff.”

At least in the future, with a few small improvements, the Pats can fight for a different ending.

Here’s what else the film revealed about the Patriots’ latest loss:

New England Patriots quarterback Drake Maye scrambles away from Buffalo Bills defensive end AJ Epenesa during the second quarter of the game at Gillette Stadium. (Nancy Lane/Boston Herald)

Drake Maye

14-of-23 for 155 yards, INT, 3 sacks, 43 rush yards (2 TDs)

Accurate throw percentage: 71.4%

Under pressure: 3-of-6 for 26 yards, 2 sacks, 17 rushing yards

Against the blitz: 3-of-5 for 53 yards, sack, 17 rushing yards

Behind the line: 2-of-2 for 23 yards

0-9 yards downfield: 9-of-10 for 66 yards

10-19 yards downfield: 2-of-5 for 36 yards

20+ yards downfield: 1-of-4 for 30 yards, INT

Notes: The return of Drake Meh.

Not seen since September, this version of Maye was pedestrian in every major area. He threw his third-highest rate of off-target passes this season, behind only his performances in wins at Cincinnati and Tampa Bay. Maye often missed a tick high — most glaringly on throws to Mack Hollins and Hunter Henry — and seemed more unsettled than usual by the threat of pressure than actual pressure (the Patriots’ 31.2% allowed pressure rate Sunday was below their season average).

The Bills often showed blitz at the line with six defenders across the line of scrimmage, then dropped at least one linebacker to protect the middle of the field and wall off any in-breakers Maye wanted on his first read. Maye was a beat slow reading their disguised mix of man and zone coverage from single-high and two-high structures pre-snap, which factored into two sacks he took. Even when Maye’s first read was clearly covered, he sometimes got stuck.

This hurt the Patriots most on their penultimate snap, a third-and-5 with less than two minutes left when Maye wanted a well-covered TreVeyon Henderson down the right sideline. As he threw incomplete, Maye missed an open Kayshon Boutte crossing over the middle. His iffy decision-making exacerbated the accuracy problem, where perhaps regression should have been expected considering Maye’s historically pinpoint season so far.

Maye, though, also took some needlessly low-percentage shots, including a long sideline throw to Hollins on third-and-1 that led to a punt in the first quarter. Those instances are cases where Maye, who can complete those throws, did what the Bills wanted him to do against man coverage because it boosted their odds of getting off the field. Every quarterback loses his touch now and then, but decisions like that, forcing a ball to Henderson and taking too long in the pocket before a sack or two, cost the Patriots, too.

New England Patriots cornerback Marcus Jones hauls down Buffalo Bills quarterback Josh Allen during the fourth quarter. (Nancy Lane/Boston Herald)

Critical areas

Turnovers: Patriots 1, Bills 0

Explosive play rate: Patriots 7.8%, Bills 6.0%

Success rate: Patriots 54%, Bills 48%

Red-zone efficiency: Patriots 2-3, Bills 5-6

Defensive pressure rate: Patriots 28.5%, Bills 32.1%

Offense

Game plan

Personnel breakdown: 54% of snaps in 11 personnel, 9.5% of snaps in 12 personnel, 4% of snaps in 13 personnel, 15.5% of snaps in 21H personnel, 17% of snaps in 22 personnel.***

Personnel production: 54% success rate in 11 personnel, 60% success rate in 12 personnel, 50% success rate in 13 personnel, 50% success rate in 21H personnel, 55% success rate in 22 personnel.

First-down down play-calls: 62.5% run (47% success rate), 37.5% pass (78% success rate)

Play-action rate: 14.3%

Josh McDaniels hit all the right pressure points in the first half.

He stressed Buffalo’s undersized defense with big personnel and a run-heavy plan. He stressed their run defense on the edges — where they had allowed 5.7 yards per carry entering kickoff — with toss plays, pin-and-pull concepts and regular outside zone calls. For a game-plan wrinkle, McDaniels dusted off an option play inside the red zone, where Maye kept the ball for the first time all season on his first touchdown and later scored on a well-executed quarterback draw that presented like a scramble.

Eventually, the Patriots finished with a 59% success rate when rushing, a season best by a gigantic margin. All of their explosive plays came off runs, excluding Kayshon Boutte’s 30-yard catch on the opening drive that may have been overturned if challenged. Thanks to timely play-calls and bruising, fundamental football, the Pats smashed Buffalo’s run defense harder than even they could have expected.

Callahan: Patriots’ loss to Buffalo brings hard lessons, needed hardship for playoff run

Which brings us to the second half: where in the world was the run game and play-action passing? McDaniels called three runs after halftime — two of which were successful — and posted his second-lowest play-action rate of the year. Back in October, the Patriots used play-action on more than 40% of their dropbacks against Buffalo and to great success. What changed?

Even accounting for the fact the offense ran just 19 plays after halftime, why were 16 of them straight dropbacks against a bottom-5 run defense while they led by multiple scores? The Patriots had 177 rushing yards at halftime, were rolling with every heavy personnel grouping, and you never would have known either based on the game McDaniels called in the second half.

Man.

Player stats

Broken tackles: QB Drake Maye 3, RB TreVeyon Henderson 2, RB Rhamondre Stevenson 2, WR Mack Hollins

Pressure allowed: RT Morgan Moses 2 (QB hit hurry), Team 2 (QB hit, hurry) RG Mike Onwenu (sack), RB TreVeyon Henderson (sack), QB Drake Maye (sack), LT Vederian Lowe (QB hit), C Garrett Bradbury (hurry)

Run stuffs allowed: Team, FB Jack Westover, TE Hunter Henry, Bradbury

Drops: Henry

New England Patriots tight end Hunter Henry is hauled down by Buffalo Bills defenders Cam Lewis and Maxwell Hairston during the second quarter of the game at Gillette Stadium. (Nancy Lane/Boston Herald)

Notes

This was the rookie running back you had been waiting for. TreVeyon Henderson’s long speed broke the game open at 21-0, then kept the Patriots alive on a cutback he made in the second half for a 65-yard score.
Henderson’s improved vision shone Sunday, and even overeager runs paid off because once he gains the corner, he was gone. A game plan that emphasized outside runs helped, but the rookie deserves credit for his best game as a pro.
The Patriots fielded Henderson and Rhamondre Stevenson together on several snaps, including three runs — all successful — though their main function again was to chip edge rushers in pass protection when leaving the backfield on routes.
Stevenson out-snapped Henderson by 10 plays, and that even split is likely here to stay despite Henderson’s production. Stevenson again delivered in blitz pickup, where the rookie allowed another sack.
Left guard Jared Wilson was the only offensive lineman to post a clean sheet in pass protection, though his run-blocking didn’t measure to the same level as some of his teammates.
Hat tips to right guard Mike Onwenu and right tackle Morgan Moses for erasing Bills linebackers at the second level to spring a couple explosive runs. That said, Onwenu’s third-quarter holding penalty that erased a completion which would have carried the offense into field goal range was a killer.
And the wide receivers? Tough day at the office, starting with their seven combined catches. The inability to defeat press coverage on the last snap, where the play was designed to beat man-to-man, was troubling.
Stefon Diggs received extra attention on a few third downs where a Buffalo safety dropped to the middle of the field and hunted crossing routes. Diggs has been a third-down binkie for Maye, who unsurprisingly struggled without him in key situations aside from a 16-yard connection in the second half.
It’s fair to wonder whether teams will copy the Bills’ fearlessness in coverage, especially considering they were down top corner Christian Benford. Maye finished 4-of-9 for 80 yards versus man-to-man, plus an 11-yard scramble.
Against man coverage, the Pats have often used DeMario Douglas out of the slot as a deep threat or run-after-catch player. So where was he? Douglas finished with 10 offensive snaps, including seven where he ran routes. He should have played more.
Down game for Hunter Henry, between his fourth-quarter drop, run stuff allowed and iffy run-blocking around that one whiff.

Defense

New England Patriots defender K’Lavon Chaisson dives for Buffalo Bills running back James Cook III during the second quarter. (Nancy Lane/Boston Herald)

Game plan

Personnel breakdown: 62% three-corner nickel package, 38% base defense.****

Coverage breakdown: 50% zone, 50% man

Blitz rate: 30.3%

Blitz efficacy: 50% offensive success rate and 3.4 yards per play allowed

Like McDaniels, defensive play-caller Zak Kuhr appeared to empty his clip in the first half and grow helpless in the second.

After a clever blitz and coverage sack dropped Josh Allen twice in the first half, the Pats could hardly manufacture pressure to disrupt him the rest of the game. Allen picked his matchups against Kuhr’s man-coverage plan and scrambled when he had the chance. The Patriots did not spy Allen, instead preferring a diverse, contain-focused rush that occasionally included blitz pressure and broke down like on Allen’s 14-yard touchdown pass in the second half.

On the ground, the Pats matched Buffalo’s big personnel with their own and dabbled with the 3-4 front they used in October to contain James Cook. But it mattered less and less as the game wore on. Their only recourse was to throw more defenders up front and increase their blitz rate in the fourth quarter, but between their interior defensive linemen becoming turnstiles and Allen’s mobility, again, little mattered.

Player stats

Pressure: DL Christian Barmore 2 (QB hit, hurry), DL Khyiris Tonga 2 (2 hurries), DL Cory Durden 2 (2 hurries), OLB Harold Landry (sack), LB Jack Gibbens (sack), LB Christian Elliss (hurry), CB Marcus Jones (hurry), CB Carlton Davis (hurry), S Craig Woodson (hurry)

Run stuffs: Team

Pass deflections: CB Christian Gonzalez, CB Carlton Davis, S Jaylinn Hawkins, LB Christian Elliss

Missed tackles: Gibbens 2, OLB Anfernee Jennings, DL Cory Dudren, Barmore, Chaisson, Davis, Tonga, Elliss, Hawkins

Notes

Block destruction and tackling. The Patriots’ fundamentals cracked too often in the second half and that, more than any play-calling or blitz design, killed them.
Buffalo’s offensive line handled them, especially when the defensive linemen lost leverage with poor pad level. All of their top defensive linemen — Christian Barmore, Khyiris Tonga and Cory Durden — looked overextended as run defenders.
The Pats’ 10 missed tackles were a season high dating back to their last loss on Sept. 21 against the Steelers. Buffalo gained 87 rushing yards after contact, per Pro Football Focus.
Tackling is where they missed Robert Spillane, a captain and their best run-fitting inside linebacker, most of all.
Another massive problem: short-yardage. Opponents have converted 88% of the time on runs with two yards or less to go this season, which is at the heart of their red-zone problems. The only time the Bills didn’t convert inside the 20-yard line was when they knelt the clock out.
Rough outing for K’Lavon Chaisson, who generated virtually no pressure and continued to get attacked as a run defender. Allen rushed for 20 yards on a designed, weakside quarterback run that targeted him in the second half.
The good: cornerbacks Christian Gonzalez and Carlton Davis posted coverage shutouts outside.
The bad: yes, it was defensive pass interference on Marcus Jones, who made contact a split second before the ball arrived on fourth down and without his head turned. Allen’s underthrown deep ball put him in an impossible spot, and were it not for the flag, Jones should’ve had an interception.
The ugly: Spilane’s replacement, Jack Gibbens, got exposed along with his defensive line in the second half. He wasn’t the only one failing to plug gaps, but his mistakes were the most glaring. His replacement on passing downs, Marte Mapu, also failed to take a deep enough drop to stop a third-and-long conversion in the third quarter.
The ugly pt. II: the Patriots’ run defense is among the league’s worst since mid-November. This was not a one-game sample, nor entirely a function of missing Milton Williams. The lack of defensive talent is catching up to them, especially against good teams.

*Explosive plays are defined as runs of 12-plus yards and passes of 20-plus yards.

**Success rate is an efficiency metric measuring how often an offense stays on schedule. A play is successful when it produces positive EPA (Expected Points Added).

***11 personnel = one running back, one tight end; 12 personnel = one running back, two tight ends; 13 personnel = one back, three tight ends; 21H = two halfbacks, one tight end; 22 personnel = two backs, two tight ends (including a sixth offensive lineman lining up as a tight end).

****Base defense = four defensive backs; nickel = five.